EXTERIOR:
Of steel-frame construction, with walls of brick, corrugated sheeting to clad the doors, the whole painted green. Multi-pitched roof with gables to the north and south elevations, dividing the building into eleven bays. To the south, facing the airfield, is a central flat-roofed annexe. This has a central double-storey portion flanked by single-storeys to the west and east. The double-storey accommodation housed the squadron's commanding officer as well as an office for the adjutant, the sergeant major, a store and a clerk's office. To the west were offices for two flight commanders, as well as two stores and an airmens' rest room. To the east the annexe housed pilots' locker rooms, air gunners' lockers, two stores a further flight commander's office and a clerk's office. The windows to the annexe have been replaced with modern double glazed units. To the north is a further single storey annexe which also has a flat roof and replacement windows. All replacement windows are not of special interest. The northern annexe housed technical functions: to the west of a central covered way was a battery charging room, boiler house, detail room, W/T (Wireless Telegraphy) workshop, store and toilets. To the east of the covered way was the gun cleaning room, workshop and a paint and dope (a plasticised lacquer applied to aircraft fabric) store. The substantial aircraft sliding doors face west and east. These are steel-framed and in six leaves, opening fully with three leaves to either side supported on projecting door gantries.

INTERIOR:
Steel structure of lattice wall stanchions at 25 feet centres support the main roof girders. Large glazed windows, arranged at clerestory level along the long north and south elevations, light the interior. Either side of each window are piers dividing the long elevations into its eleven bays. In February 2009 internal dividing walls of steel pier construction, were being erected to divide the former single interior space into three to accommodate an eastern storage bay, a central spray shop, and with a contingency space to the west . These modifications are not of special interest. Steel truss roof with cross bracing. The roof is understood to have timber purlins and boarding and to be clad with asbestos slates (Francis 2008, 90).

HISTORY:
The outbreak of the First World War in 1914 and the inevitable rapid expansion of the Royal Flying Corps (the predecessor of the RAF) led to the selection and requisition of a number of new airfields in England. One such was at Northolt where land was acquired by the War Office from February 1914 with the landing ground operational by the following month although accommodation was initially temporary and basic. The airfield was laid out on a north-south alignment with the aircraft sheds aligned west-east to the north of the flying field. Further land was requisitioned as the airfield expanded. During the First World War Northolt was primarily a training airfield for pilots to be then deployed to the Western Front. Latterly it housed fighters to intercept Zeppelin airship bombing raids. Northolt became one of ten such 'air defence stations' surrounding London, this arrangement being known as the 'London Air Defence System'.

In the inter-war period Northolt functioned as both a military and civilian airfield with a flying school. The site was occupied by both a bombing and a fighter squadron as part of the 1920s RAF expansion plans, and considerable enhancement of the buildings took place. Further expansion, between 1928 and 1934, resulted in the construction of further buildings including the Pilots' Room and Watch Office (building 23). The Operations Block (building 27) was also completed by 1928, having been designed in 1924 although it is not clear how rapidly construction began. During the late 1920s to early 1930s Northolt took on the role of the transportation of senior government officials and the royal family, and this traffic increased when it became London's wartime airport. The station's most significant role at this time however, was its participation in numerous trials and air exercises associated with the development of the 'Dowding' system; the Integrated Air Defence System or IADS (see below).

Northolt was a key fighter station as part of 11 Group, RAF Fighter Command which covered the south-east of England and was commanded by Air Chief Marshall Sir Keith Park. (Fighter Command had been established in 1936 to organise the country's fighter stations in a number of regional groups with a central command based at RAF Bentley Priory. Other Commands covered Bomber, Transport and Training.) Northolt, acting in association with Uxbridge and RAF Bentley Priory, was very much in the front-line during the Second World War. The station's fighter squadrons played a key role throughout and were notable for their success in destroying enemy aircraft, with limited losses, during the 1940 Battle of Britain. Northolt was the first airfield to house operational Hurricanes and was also the home to Polish Fighter Squadrons. In 1943 it became the main terminal for RAF Transport Command but also remained a fighter station until March 1944. In the same year it became the home of a number of air photographic reconnaissance detachments from RAF Benson charged with the gathering of imagery of key events in the battle for the liberation of north-west Europe, namely the D-Day landings, Arnheim and the Rhine crossings. Inevitably Northolt continued to expand during the Second World War, the most significant development being the construction of two concrete runways. The accommodation was enhanced also, but all post-1940 buildings were either of a temporary brick construction or were prefabricated.

In 1945 the government decreed that Northolt and Croydon should operate as London's airports. Broadly Croydon was used by UK airlines and Northolt by European Services and foreign airlines. By 1952 Northolt had become the busiest airport in Europe but from then on, as the new airport at Heathrow became gradually operational, more civilian flights transferred there such that Northolt could revert to the RAF by October 1954 and by October of the following year all civilian flying ceased. The site remains an operational RAF station with its VIP transportation role still a significant function.

This C-type hangar was constructed as part of the mid to late 1930s expansion scheme with an estimate for the works, of £21,000 for a 200 foot shed, submitted in 1934. The final design, of 1935, was for a 300 foot shed as it was intended to house two squadrons. It was designed by the Ministry of Works (one B. C. Jacklin is known to have been involved) to accommodate both single-seater fighter aircraft and also space for aircraft development. It was first occupied in November 1938 which provides a date by which it had been completed. In form it resembles a design more commonly associated with bomber airfields with the squadrons' accommodation in the hangar annexes. Throughout the Second World War the hangar was used to house Churchill's personal aircraft in which he flew to many important meetings of the Allied leaders. During 1946 the hangar was partly allocated to BOAC (British Overseas Airways Corporation) and partly to RAF Transport Command. In the early to mid 1950s this hangar was occupied by the RAF's VIP Flight. At the time of the February 2009 inspection visit alterations were being undertaken internally to divide the hangar into three.

REASON FOR DESIGNATION:
The C-type hangar (building 5) at RAF Northolt is listed at Grade II for the following principal reasons:
* Architecture: a building representing the earliest (1934) form of C-type hangar design, a hangar type that was to become the most commonly built and successful RAF hangar. One of only five of this early design surviving nationally;
* Historic Interest: The only surviving large hangar at RAF Northolt which was operational during its key Second World War action, housing both single-seater fighters and Churchill's personal plane in which he travelled to important meetings of the Allied Leaders;
* Group Value: visual and historic functional relationship with the Operations Block (building 27) and Squadron Watch Office (building 23, which served the now demolished A-type hangar).

Selected Sources

Legacy Record - This information may be included in the List Entry Details

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